You will notice discreet signs in many bathrooms and kitchens asking you to preserve water. Water is a precious resource on these islands with no lakes or rivers and few springs. Most homes, and a good many businesses, have cisterns—large concrete storage tanks—below their floor slabs, where rainwater collected on the roof is stored. In times of rain, cisterns can sometimes overflow. In times of drought, every last drop is rationed. Cistern water is generally used for showers, washing, cleaning, and flushing. It should be boiled for drinking.
The other main source of freshwater is seawater desalination plants, which use reverse osmosis technology to make freshwater out of saltwater. In the British Virgin Islands, most of the public water supply comes from a series of desalination plants around the territory. Desalinated water is safe to drink and does not taste salty, although it does not necessarily taste good either.
Despite the existence of technology to make freshwater from the ocean, water is still considered a precious resource, if for no other reason than if your cistern should run dry, it is expensive to buy. Guests should do their part to conserve water.